Solution-based synthetic strategies for one-dimensional metal-containing nanostructures

Abstract

One-dimensional (1D) nanostructures, such as nanowires, nanotubes, nanorods, and nanoribbons, have attracted significant attention stemming from the plethora of interesting size-dependent and, more importantly, structure-related properties resulting from confinement effects. In particular, the novel properties of 1D nanostructures of metals and metal oxides (binary and ternary) render them as prime candidates for a wide range of applications including the fabrication of nanoscale devices associated with solar cells, energy storage, fuel cells, molecular computing and information storage, medical imaging, diagnosis and detection, drug delivery, sensors and catalysis. Thus, it has been simultaneously necessary and critical to create synthetic protocols for the production of these materials which not only are reliable and reproducible, but also can generate compositionally pure, monodisperse, highly crystalline products of a desired 1D morphology. Solution-based methodologies have demonstrated significant advantages over other approaches, as they are facile, simple, flexible, 'green' by nature, and can be applied to a wide range of nanomaterials with diverse chemical compositions. Moreover, these methods can often be scaled so as to produce large quantities of products which are advantageous from an applications' standpoint. Herein, we present synthetic advances associated with solution-based approaches. Specifically solvothermal/hydrothermal, molten salt, electrospinning, template-directed, solution/one-pot, and sol-gel methodologies are discussed with the primary goal of achieving the reproducible synthesis of 1D motifs of metals, binary metal oxides, and ternary metal oxide systems.

Molten Salt Synthesis of Ceramic Powders

“…The application of molten salt synthesis is widely spread since 2005, from ferroelectric and ferromagnetic materials to materials for Li-ion batteries (Santhanam & Rambabu, 2010), www.intechopen.com semiconductors (Huang et al, 2010), phosphors (Yan & Lei, 2010), and photocatalysts (Arney et al, 2008), especially with regard to nano-sized materials . Although this review only deals with complex oxides, the application has been extended to simple oxide powders with specific morphology (Tiano et al, 2010). The preparation of nanoparticles with various shapes (equiaxed, wire, strip, plate) has been reported for a wide variety of materials.…”

“…Two mechanisms of particle formation are reported during the reaction stage, and Ostwald ripening is the main mechanism during the particle-growth stage. Powders with the desired morphology (size and shape) can be obtained by the precise control of the reaction conditions in these stages (Tiano et al, 2010). Figure 7 shows the schematic diagram of the formation of product particle P from reactants A and B.…”

Painting by Numbers: Nanoparticle‐Based Colorants in the Post‐Empirical Age

“…However, it is only with recent developments in the synthetic control of particle morphology that the true infl uence of reduced symmetry can be explored. Indeed, with the huge range of nanostructure morphologies now attainable including wires, rods, fl akes and multipods, [ 43 ] − [ 45 ] it is a daunting task to identify which may be worth exploring. Added to this is the further dimension of complexity provided by the possibility to coat spherical or non-spherical particles either partially, [ 46 , 47 ] or fully with another functional material.…”

Tuning the Morphology of Metal Oxides for Catalytic Applications

“…[13][14][15][16][17][18][19][20] According to the growing mechanism of nanocrystals in liquid solution, the morphology of the catalyst nanoparticles can be kinetically modulated by adjusting the growing rates along specific orientations. 21,22 In other words, the desired crystal planes can be selectively exposed in a large fraction through morphology-controlled synthesis of catalyst particles using the bottom-up approach in liquid solution.…”

“…Moreover, these precious metal nanoparticles are typically used for liquid-phase reactions that are conducted at relatively lower temperatures, favoring to maintain their sizes and shapes. Several recent articles have comprehensively reviewed the progresses on the fabrication of precious metal nanoparticles, 5,6,[12][13][14][15][16][17][18][19]34,35 their applications in heterogeneous catalysis [30][31][32][33][34] and electrocatalysis. [36][37][38][39] However, such a morphology-dependent behavior has been scarcely applied to metal oxide nanoparticles.…”